Sharpening device for knives



Feb. 10, 1948. E. w. CLARK 2,435,672

SHARPEiNING DEVICE FOR KNIVES Filed April 4, 1946 6M2 N. CLML,

.the blade and the abrasive members.

Patented Feb. 10, 1948 UNITED STATES PATENT. OFFICE 2,435,612 SHARPENING I)I '1.VI(.JI:. on Knives 7 Earl w. Clark, Stuart, Fla. I Application April' i, 1946, Serial No. 659,492

rasive members and the knife blade are so guided that the cutting edge of the knife blade maybe drawn over the grinding surfaces in a selectedangular relationship thereto and the weight of the abrasive members exerts pressure between The primary objects of my invention are: To provide a mechanism whereby a substantially uniform pressure is maintained between the blade and the abrasive member. A further object is to provide improved guiding for the knife blade and an additional object is to provide for uniform Wear on the abrasive members.

I attain these objects by the mechanism illustrated in the accompanying drawings in which:

Fig. 1 is a sectional elevation of the sharpening device taken on line 1-! of Fig. 3. Fig. 2 is an end elevation of the device shown in Fig. 1. Fig.

3 is a plan view of the device shown in Fig. 1. Fig. 4 is a side view of one of the abrasive members. Fig. 5 is an end view of member shown in Fig. '4. Fig. 6 is a side view of a flanged guide roller. Fig. 7 is a side view of one of the positioning stops.

Similar numerals refer to similar parts throughout the several views.

The abrasive members I are made up of abrasi've particles held together by a suitable binding material. By making the abrasive members of square prism shape, as shown in Figs. 4 and 5, four sides of each abrasive member may be used for blade sharpening. Other shapes can obviously be used however. Mounting or holding means for the abrasive members I are made up of: a bent rectangular steel bar 2 which is so bent as to provide a support for the abrasive member at its lower end and also near its top and to provide an outwardly and upwardly inclined portion which engages flanged guide rollers 3, which are provided with flanges and turned down necks or journal as shown in detail in Fig. 6; clamps 4 and bolts 5. The frame for the sharpening device is made up of sides 5, spacer and base forming members .1 and rivets 8. Frame sides 6 are provided with holes which form bearings for the journals of flanged guide rollers 3. Slots 5a in frame sides 6 form guides for the knife blade l0 and maintain the blade in proper relationship to the abrasive members during the grinding operation. Stops 9. which are shown in detail in Fig. 7, contact the abrasive members on their grinding faces and position the abrasive members so that the knife blade It, as it is 4 Claims. (01. 51- 214) brought down slots 6a. and into contact with abrasive members I, may force opposing abrasive members apart. The outwardly and upwardly inclined portion of bent bar 2 co-acting with guide rollers 3 form a. guiding means that causes the abrasivemembers l to move outwardly and. upwardly topositions shown by dot and dash lines when knife blade 10 is drawn over the whole length of the grinding faces of abrasive memhers I. Since the abrasive members are raised to a higher.v elevation as theyare forced apart bythe knife blade the abrasive members will always exert a substantially uniform pressure on the knife blade. Thisuniform pressure results in uniform wearing down of the grinding faces of the abrasive members. The grinding faces will thus retain their original contour and the selected angleat which the grinding faces are inclinedto the knife blade is thus maintained substantially constant as the abrasive members are worn down by successive knife sharpening. I have found that grinding the cutting edge of the knife blade to an included angle of about forty degrees gives a sharp and durable cutting edge for kitchen and pocket knives and the like and I have inclined the abrasive members so as to grind the knife blade at substantially the above mentioned included angle. By providing knife guiding slots 6a on each side of each abrasive member I provide a maximum of guiding for the knife blade which is essential for accurate grinding.

While I have for simplicity in the drawings shown only two abrasive members to each sharpening unit an additional abrasive member may be added by providing: one additional frame side Ii, one frame base 1, lengthening rivets 8, three additional guide rollers 3, one stop 9, one abrasive member'l, and mounting means consisting of parts 2, 4, and 5. Three abrasive members are essential in order to grind both sides of the cutting edge close to the handle and close to the point end of blade. With my improved arrangement of blade guides the blade spans a shorter distance between supports and hence is deflected a minimum amount by the pressure of the abrasive members. Further, when sharpening at or near the point the blade will be guided by two guiding slots and hence will be held in a definite relationship to the grinding faces. When only two knife guides are used to a sharpening device that is a guide on the outside of each outside stone the point of the blade cannot be properly guided.

What I claim is:

1. In a knife sharpener: a frame comprising a base having a plurality of upwardly extending portions, said upwardly extending portions having transversely aligned vertical knife guiding slots in said portions located midway of the horizontal lengths thereof; a plurality of carriers with abrasive members mounted thereon, said carriers and abrasive members being disposed be-' -:'base having a t'pluralityof :upwardlywxtending portions; said upwardly extendingportions ,hav- "ing transversely -;.aligned verticaL-knife :guiding *s'lots in said port-ions locatedTllldWEtYfOfthGzhOlF 1 rzontal length thereof aa plurality of carriers'with abrasive members: mounted thereoniandzwithr ad- 'jacent abrasive members.opposit-elyidisposedflelnative to, and with*theirxworkinga'facesin planes which intersect -:atc:an :acute zanglegthe vertical plane of said'knife guiding-slotsy-anuoutwardly and upwardly inclined guidememberronr said :car-

riers; said carriers and abrasiveimem'bers being disposed between adjacent pairs-'of-said upwardly extending-portions; 'guide rollers-disposed between adjacent pairs of' said upwardly extending portions and pivotally"journaled therein and'said guide rollers 'disposed'to contact-the upperand lower surfaces of-said guide members.

'3.In a knife sharpener: a frame comprisinga base 'having a plurality of upwardly extending portions, said upwardly extending portions having transversely aligned vertical knife guiding slots in said portions located midway of the horizontal length thereof; a plurality of carriers with abrasive members mounted thereon and with adjacent abrasive members oppositely disposed relative to, and with their working faces in planes which intersect at an acute angle, the Vertical plane of said knife guiding slots; a guide member .onzsaid carriersy said carriers -:and abrasive members being disposed between adjacent pairs of said upwardly extending portions; guide rollers "disposed between adjacent pairs of said upwardly i'extending portions and pivotally journaled therein and said guide rollers disposed to contact "the upper and lower surfaces of said guide members.

4. In a knife sharpener: a frame comprising a base having a pluralit of upwardly extending portions, said upwardly extending portions hav- :ing' transversely :a'ligned vertical knife iguiding slots in said portions locatedimidway of' the horizontal length: thereof a plurality of 'carrierswith abrasive members mounted thereon andwith adjacent:abrasive-"members oppositely disposed relative' ;to,.= and with their working faces: in planes which "intersect at :an acute angle, the vertical plane of saidknifezguiding slots, said carriers and abrasive members being disposedbetween adjacent pairs of said upwardly extending portions;

an outwardly and upwardly inclined guidermember on said'carriers; guide rollers 'disposed b'etween 'adjacentpairs of said upwardly extending portions and pivotally journaled therein; and said guide rollers disposed to contact the upper and lower faces of said guide members; and-stop means fixed relatively to' said knife guiding-slots and disposed to contact *the working facesof said abrasive members.

EARL; W." CLARK. 

